How severe is CVE-2026-33123?

CVE-2026-33123 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-33123 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-33123?

CVE-2026-33123 affects Pypdf Project Pypdf. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-33123?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-33123 have an EU (EUVD) identifier?

Yes. CVE-2026-33123 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13651.

When was CVE-2026-33123 published?

CVE-2026-33123 was published on 2026-03-20 and last updated on 2026-06-17.

CVE-2026-33123

CVE-2026-33123 is a medium-severity vulnerability in Pypdf Project Pypdf with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-400.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v4: 5.1
EPSS exploit prediction: 0% (27th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-13651
Weakness: CWE-400
Affected product: Pypdf Project Pypdf
Published: 2026-03-20
Last modified: 2026-06-17

Description

pypdf is a free and open-source pure-python PDF library. Versions prior to 6.9.1 allow an attacker to craft a malicious PDF which leads to long runtimes and/or large memory usage. Exploitation requires accessing an array-based stream with many entries. This issue has been fixed in version 6.9.1.

Frequently asked questions

What is CVE-2026-33123?: pypdf is a free and open-source pure-python PDF library. Versions prior to 6.9.1 allow an attacker to craft a malicious PDF which leads to long runtimes and/or large memory usage. Exploitation requires accessing an array-based stream with many entries. This issue has been fixed in version 6.9.1.
How severe is CVE-2026-33123?: CVE-2026-33123 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-33123 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-33123?: CVE-2026-33123 affects Pypdf Project Pypdf. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-33123?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-33123 have an EU (EUVD) identifier?: Yes. CVE-2026-33123 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13651.
When was CVE-2026-33123 published?: CVE-2026-33123 was published on 2026-03-20 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:pypdf_project:pypdf:*:*:*:*:*:*:*:*

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